Re: [PATCH 2/2] staging: rtl8723bs: fix OOB read in OnAssocRsp() IE loop

[Luka Gejak]

On Mon Apr 20, 2026 at 4:08 PM CEST, Alexandru Hossu wrote:
> The IE parsing loop in OnAssocRsp() advances by (pIE->length + 2) each
> iteration but only guards on i < pkt_len.  When a malicious AP sends an
> AssocResponse whose last IE has only one byte remaining in the frame (the
> element_id byte lands at pkt_len-1), the loop reads pIE->length from
> pframe[pkt_len], which is one byte past the allocated receive buffer.
>
> Additionally, even when the header bytes are in bounds, pIE->length itself
> can extend the data window beyond pkt_len, silently passing a truncated IE
> to the handler functions.
>
> Add two guards at the top of the loop body:
>   1. Break if fewer than sizeof(*pIE) bytes remain (can't read the header).
>   2. Break if the IE's declared data extends past pkt_len.
>
> Signed-off-by: Alexandru Hossu <hossu.alexandru@xxxxxxxxx>
> ---
>  drivers/staging/rtl8723bs/core/rtw_mlme_ext.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
> index 5f00fe282..9666226a6 100644
> --- a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
> +++ b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
> @@ -1400,7 +1400,11 @@ unsigned int OnAssocRsp(struct adapter *padapter, union recv_frame *precv_frame)
>  	/* to handle HT, WMM, rate adaptive, update MAC reg */
>  	/* for not to handle the synchronous IO in the tasklet */
>  	for (i = (6 + WLAN_HDR_A3_LEN); i < pkt_len;) {
> +		if (i + sizeof(*pIE) > pkt_len)
> +			break;
>  		pIE = (struct ndis_80211_var_ie *)(pframe + i);
> +		if (i + sizeof(*pIE) + pIE->length > pkt_len)
> +			break;
>  
>  		switch (pIE->element_id) {
>  		case WLAN_EID_VENDOR_SPECIFIC:

LGTM.

Reviewed-by: Luka Gejak <luka.gejak@xxxxxxxxx>

Best regards,
Luka Gejak